Polyethylene glycol/surfactant mixtures improve lung function after HCl and endotoxin lung injuries

Addition of nonionic polymers such as polyethylene glycol (PEG) and dextran ameliorates inactivation of Survanta by a variety of substances in vitro. Addition of polymers to Survanta also improves pulmonary function when used to treat rats with lung injury caused by instillation of human meconium. To find whether this approach is effective in lung injuries that more closely resemble adult respiratory distress syndrome (ARDS), we have compared the use of Survanta with Survanta + PEG in two additional models of lung injury caused by either lipopolysaccharide (LPS) or HCl in adult rats. Significant improvement of serial measures for arterial oxygenation and of postmortem pressure-volume measurements were found after treatment with Survanta + PEG compared with Survanta alone. PEG added to Survanta increased resistance to inactivation caused by tracheal fluid taken from animals injured with HCl. Other work suggests that PEG promotes surfactant aggregation, separates surfactant from surfactant inhibitors, and enhances access of surfactant to the gas-liquid interface. The addition of polymers to surfactants may also be useful in the treatment of lung injury where inactivation of surfactant has already occurred.